Emanuele Maiorana

Fatigue strength of corroded bolted connection

This note summarizes some recent investigation results on the behavior of corroded steel bolted joints under uniaxial fatigue loading. Fatigue test specimens, were made up using S355 structural steel plates joined together with preloaded M12 bolts of class 10.9 with a geometry that corresponds to the Δσ = 112 MPa EC3 detail category. The accelerated corrosion process was accomplished using an electrolyte consisting of an aqueous 5% NaCl solution whereby the specimens were treated. In particular, during the corrosion process specimens were repeatedly immersed for 2 minutes in the electrolyte and then removed keeping them 60 minutes long in free air at 35 °C. An atmospheric corrosion in marine-industrial environment is wellrepresented through corrosion test. Fatigue loading tests and surface morphology measurement of uncorroded and corroded specimens were performed and the results were compared.

Comparison between Eurocodes and North American and Main International Codes for Design of Bolted Connections in Steel Bridges

Bolted joints are broadly used for the connections of structural elements in steel bridges. Rules for design of bolted connections are currently under discussion in Europe for improving Part 1-8 of Eurocode 3, which deals with the sizing and structural design of joints. In this work, a wide comparison is made between the Eurocode and the codes of Italy, the United States, Canada, Australia, and Japan. General descriptions of the design criteria for typical connections in bridges related to materials, geometrical limitations, slip, shear, and bearing resistance are presented. An illustrative example to compare the various code provisions is given to quantitatively show their performance for a practical case.

Experimental tests on slip factor in friction joints: comparison between European and American Standards

Friction joints are used in steel structures submitted to cyclic loading such as, for example, in steel and composite bridges, in overhead cranes, and in equipment subjected to fatigue. Slip-critical steel joints with preloaded bolts are characterized by high rigidity and good performance against fatigue and vibrational phenomena. The most important parameter for the calculation of the bolt number in a friction connection is the slip factor, depending on the treatment of the plane surfaces inside the joint package. The paper focuses on the slip factor values reported in European and North American Specifications, and in literature references. The differences in experimental methods of slip test and evaluation of them for the mentioned standards are discussed. The results from laboratory tests regarding the assessment of the slip factor related to only sandblasted and sandblasted and coated surfaces are reported. Experimental data are compared with other results from the literature review to find the most influent parameters that control the slip factor in friction joint and differences between the slip tests procedures.